If you're flexible about where exactly the "doorman monster" appears, you could have a vestibule or portico, with the animated armor that others mentioned earlier. Some additional options:
Rosebushes (or perhaps something more noxious, like oleander?) that are actually treants/"leaf elementals"/haunted "trees."
The facade is actually a wood elemental in plank form; damaging it causes it to lose limbs, which crawl back to the house to reform the facade.
Any other kind of statue, including the aforementioned weeping angels or cherubs, but also possibly heraldic creatures (bear, lion, chimaera, eagle, etc.) or something a little more fantastic (manticore, miniature dragon, displacer beast).
The house's door has semisentient shadows guarding it--if people look closely, as long as there's enough light, they may notice that the statues have two shadows...and that when they get close enough, suddenly they have two shadows. Then the shadows rise up and attack, boxing the party in at the entrance.
Some kind of noxious vine, possibly alchemical or magical in nature, with gourds (of course!)--the gourds rise up and attack, a macabre mirror of Cinderella.